Firing pin safety device for breech mechanisms



April 23, 1957 J. M. EDMUND FIRING PIN SAFETY DEVICE FOR BREECH MECHANISMS Filed Oct. 29, 1954 2 Sheets-Sheet 1 l m F I NVENT'OR JAMES M. EDMUND ATTORNEYS April 23, 1957 J. M. EDMUND 2,

FIRING PIN SAFETY DEVICE FOR BREECH MECHANISMS Filed Oct. 297, 1954 2 Sheets-Sheet 2 FIG. 2

INVENTOR JAMES M. EDMUND the accompanying drawings wherein:

Unite FIRING PIN SAFETY DEVICE FOR BREECI-I MECHANISMS James Edmund, Montgomery County, Md., assignor to the United States of America as represented by the Secretary of the Navy Application October 29, 1954, Serial No. 465,763

6 Claims. (Cl. 89-27) (Granted under Title 35, U. S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

States PatentO Patented Apr. 23, 1957 ice and has a vertical well 14 to receive a vertically recipro-' cable breechblock 15. The upper surface of the breechblock is provided with a rounded central portion 16 forming a saddle which moves into alignment with the interior of the barrel 10 when the breechblock is in its lowermost position. The housing is provided with an after opening 17in alignment with the barrel 10 and through this 3 opening a powder case is inserted before the breech is 7 be employed to conduct an electric current to the primer to electrically fire the powder case if desired.

The present invention is directed to breech mechanisms 4 and more particularly to breech mechanisms used with catapult devices for explosively catapulting aircraft.

In the operation of explosive ordnancedevices it is very important that the devices be prevented from premature or unintended operation since severe damage to personnel. and equipment may result from such operation.

I Furthermore it is very important that a safety device utilized to prevent unintended firing of an ordnance item be simple and eifective in operation so as to prevent incapacitating the ordnance item at a critical time when it is most needed.

The present invention provides means for rendering inefiiective the usual breechblock firing pin employed for powder cases in catapult mechanisms or guns whereby, through the use of the present invention, the usual firing pin is immobilized and kept from setting oif the primer of the powder case unless the breechblock is in its closed position. As illustrated the present invention will effec- The firing pin 19 is encased within and insulated from a flanged cocking sleeve 21 which is surrounded by a firing spring 22. The cocking sleeve may be pulled to the right to compress the spring 22 and be in ready contively prevent either percussion firing by the striking of the firing pin against the primer or electrical firing through the application of electric firing current to the firing pin.

It is an object of the present invention to provide means for immobilizing the firing pin of a breech mechanism at all times except when the breech is in closed and locked position.

Another object is to .provide means for immobilizing the firing pin, said means being operated by movement of the breechblock from closed to open position.

Still another object of the present invention is to provide a simple, foolproof and automatic firing pin immobilizing means which is carried by and moves with the breechblock and is actuated by movement of the breechblock out of its breech locking position.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed descriptionwhen considered in connection with Fig. 1 is a vertical sectional view taken along a vertical center line of a breech mechanism embodying the present invention;

Fig. 2 is an enlarged longitudinal vertical section showing a firing pin in the primer contacting position;

Fig. 3 is a view similar to Fig. 2 showing the primer pin retracted by the devce of the present, invention; and

Fig. 4 is a perspective view from the opposite side of a firing pin, retracting lever and actuating-cam.

In the embodiment illustrated in the drawings there is shown in Fig. 1 the breech end of a barrel 10 which is adapted to receive a powder case 11 having a base flange 12. A portion of the periphery of the barrel is threaded to receive a housing 13 which extends beyond the barrel the breechblock 15. The lower end of the firing pin 1 dition for firing. It is retained in such position by a suitable sear mechanism (not shown) which engages the cocking sleeve lug 23 and retains it in retracted position until the trigger is pulled to release the pin and fire the powder case.

The cocking sleevemoves in a bearing 24 and, at'the outer end of the device is provided a suitable manual cocking handle 25 which when retracted compresses the firing spring 22 and moves the cocking sleeve lug 23 into registry with the usual sear.

It will be apparent with the above construction that tripping the sear will cause percussive firing of the powder case primer to fire the catapult. Also, any contact of the insulated firing pin with the powder case primer will allow electric current applied at the opposite end of the firing pin through a suitable terminal 26 to cause electrical firing of the primer. In order to prevent premature firing by either of the above methods there is provided a firing pin retracting lever 27 shown in detail in Fig. 4 as having an inturned end portion 28 which engages behind a depending extension 29 of the cocking handle so that movement to the right of the firing pin retracting lever as indicated in Fig. 3 bodily moves the cooking handle 25 and its attached firing pin 19 to the right, withdrawing the tip of the firing pin completely from the opening 20 so that electrical contact cannot be made and compressing the firing spring 22 so that even upon release of the sear by actuation of the trigger the firing pin may not move to the left to percussively detonate the primer.

The firing pin retracting lever 27 is preferably of the general shape indicated in Fig. 4 and is provided at its lower end with a transversely extending pivot 30 which mounts in a bracket 31 positioned on the underface of retracting lever 27 is recessed at 32 and provides a space for a roller 33-for engagement with a cam 34 in a manner hereinafter to be described.

Referring again to Fig. 1 there is shown a breechblock raising and lowering link 35 connected to the undersurface of the breechblock by a pin 36 and connected by pin 37 to one arm of a bell crank 38 pivoted at 39 to an extension 40 of the housing and coupled by means of pin 41, link 42 and pin 43 to a breechblock actuating piston and shaft 44 reciprocable within a hydraulic cylinder 45.

In operation it will be apparent that the admission of hydraulic fluid through opening 46 of cylinder 45 will move the piston and rod 44 downwardly to rotate the bell crank and raise the breechblock 15 into position.

ease-Ars- Since the linkage is such that the pin 37 may pass slightly past center there is provided a toggle connection which prevents unintended downward movement of the breech-- block. To open the breechblock fluid is admitted through port '47 into cylinder 45 to raise the piston and piston rod 44 upwardly and swing the bell crank am down wardly and lower the breechblock.

Adjacent the upper end of the breechblock opening and closing link 35 is provided a firing pin retracting cam 34 having a sharply inclined cammed edge portion 9 which engages with roller 33 on the firing pin retractingflevei' 27 as aforesaid and, because of the shape of its upper-- surface this cam lifts the roller 33, pivoting lever 27.

about pivot point 30 and moving the upper end 28 outwardly to withdraw the firing pin to the position illustrated in Fig. 3.

It will be seen that when the breechblock operating mechanism is actuated to open the breech, the links 35 and 38 move a substantial distance from their past center position before downward travel of the breechblock begins. During this initial movement of the linkage the sharply inclined edge portion 9 of cam 34 is displaced under the roller 33, instantly raising the roller to its uppermost position on the uppersurface of retracting cam 34 and actuating the retracting lever 27 to its maximum retaining position. Thus, the firing pin is actually rendered ineffective before the breechblock opening move= ment is begun. This is a particularly important feature since the firing pin is aligned with the primer for only a short period of time during its downward movement and it is at this time that it is imperative that unintentional firing or forward movement of the firing pin be prevented.

It will be apparent that with the above-described arrangement lowering of the breechblock automatically and instantaneously withdraws the firing pin to an inoperative position and prevents accidental firing of the case whenever the breech mechanism is not tightly closed. Also, if desired with this arrangement the act of lowering of the breechblock may also serve to cock the firing plunger by moving the cocking sleeve lug back sufiiciently to cause engagement with the sear.

Obviously many modifications andvariatio'ns of the present invention are possible inthe light of the above teachings. It is therefore to be understood that within the scope of the appended claimsthe invention may be practiced otherwise than as specifically described.

What is claimed is: 1. In a powder case breech mechanism wherein a breechblock having a powder case firing pin mountedtherein moves into and out of breech closing position thecombination of, breechblock operating means for moving the breechblock into and out of breech closing position, a cam actuated by the breechblock operating means before opening movement of the breechblock, and'a'fir ing pin stop member moved into firing pin restraining position by said cam during initial movement of the breechblock operating means and before opening movement of the breechblock and moved into noure'straining' relation to said firing pin upon the completion of the closing movement of the breechblock operating means.

2. Firing pin restraining means for a breech mecha'-' nism wherein a movable breechblock may be transported into and out of engagement with a breech comprising, means for moving the breechblock into and out of engagement with the breech, said means operating a predetermined period of time before disengaging movement of the'breechblock is initiated, a-firing pin' mounted in the breechblock and engageable withthe primer of a powder case to be fired when the breechblock is' in engagement with the breech, means normally urging the firing'pin forward toward the powder case, restraining means" for limiting forward movement of said firing pin, and cam 'means actuated by said breechblock operating means during the initial operation thereof to cause the restraining means to limit movementv ofthe firing pin toward the powder case prior to disengaging movement of the breechblock.

3. A firing pin detent for a powder case breechblock wherein a breechblock mounted firing pin is movable intoand out of powder case engagement comprising, a detent arm inturned at one end to engage with the firing pin and having a downturned intermediate portion to extend along the rear face of the breechblock, a pivotal mounting for the detent arm on the undersurface of the breechblock, and a cam roller at the other end of the detent arm, breechblock operating means for moving the breechblock into and out of breech closing position, said operating means being so arranged as to permit a predetermined period of initial operation before movement of the breechblock, and cam means disposed on said breechblock operating means for engaging said cam roller during initial operation of the breechblock operating means to thereby pivot the arm'about said mounting and obstruct forward movement of the firing pin prior to movement of the breechblock; I

4. In a breech mechanism wherein a movable breechblock may be transported from an open to a closed position-a firing pin locking means comprising, means for moving the breechblock into and out of engagement with the breech, a firin pin mounted in the breechblock and engageable with the primer of a powder case to be fired when the breechblock is in closed position, resilient means normally urging the firing pin forward toward the case, locking means for preventing forward movement of said firing pin, and cam means actuated simultaneously upon operation of the breechblock operating means to cause the locking means to instantly prevent movement of the firing pin toward the powder case.

5. In a powder case breechblock mechanism wherein a breechblock mounted firing pin is movable into and out of powder case engagement a firing pin detent comprising, a detent arm inturned at one end .to engage with the firing pin and having a dow'nturned intermediate portion to extend along the rear face of the breechblock, a pivotal mounting for the detent'arm on the undersurface of the breechblock, and a cam follower at theother end of the detent arm, breechblock operating means, means disposed on said breechblock'operating means for engaging said cam follower thereby to pivot the arm' about said mounting and obstruct forward movement of the firing pin prior tomovement of the breechblock from powder case engagement.

6. Ina breech mechanism for a powder case whereina breechblock having a powder case firing pin mounted therein moves into and out of breech blocking position the combination of, operating means for moving the breechblock into and out of breech blocking position, said operating means comprising pivoting link members, said 'link' members being disposed in a past center position when the breechblock is in breech blocking position and movable a predetermined distance therefrom before movement of the breechblock from breech blocking position, a firing pin detent and cam means carried by one of said link members for engaging said firing pin detent during initial movement of the link members from their past center position to thereby prevent actuation of Saidfiring pin simultaneously with movement of said breechblock from its breech blocking position.

References Citedinthe' file of this patent UNITED STATES PATENTS 2,279,352 Summerbell Apr. 14, 1952 

